const arr = new Array(100)
console.time('for')
for (let i = 0; i < arr.length; i++) {
  // arr[i] = i
}
console.timeEnd('for')
console.time('for of')
for (let item of arr) {
    // item = item + 1
}
console.timeEnd('for of')
console.time('forEach')
arr.forEach((item, index) => {
    // arr[index] = item + 1
})
console.timeEnd('forEach')